% subsection of Project Overview Statement

\section{Problem}\label{sec:problem}


  To support large sensor networks the Sensor Abstraction Layer (SAL) can be
  used to simplify sensor network access, control and management. It reduces the
  effort to integrate different sensors by abstracting the underlying
  technology. Once SAL has identified the sensors data can be collected by SAL.
  The problem is now how can a huge amount of data be transmitted to various
  consumers. One of the consumers would be the SRB, a data repository where all
  this sensor data can be stored and easily accessed.


\subsection{Scope}

The general aim of this project is to connect various sensors to various
consumers. SAL is already established to gather data from different sensor types and
make them accessable in an unified way. The task is to set up a middleware
between SAL and any possible consumers. Data that is collected from any sensor
has to be published in this middleware. The SRB will be a consumer that
retrieves the data and stores it for later processing. DataTurbine will be the
middleware of our choice, because it is the favorite product of our client.

\begin{figure}[htb]
	\centering
		\includegraphics[width=0.4\textwidth]{figures/design_2.pdf}
	\caption{System Overview}
	\label{fig:design_2}
\end{figure}

\begin{description}
  \item[SAL] The Sensor Abstraction Layer (SAL) provides a coherent and
  consistent programming interface to access sensors and instruments regardless
  of their types and technology. SAL documentation is available at \cite{SAL}.

  \item[SRB] is an application which provides a logical interface to
  heterogeneos storage devices. The most defining feature of SRB is the MCAT
  (Metadata Catalogue) which allows complex metadata descriptions to be attached to files stored by SRB. The most common usage of SRB is as a Distributed Logical File System (a synergy of database system concepts and file systems concepts) that provides a powerful solution to manage multi-organizational file system namespaces.
  \cite{SRB}

  \item[Data Turbine] is a robust open-source streaming data middleware system that
  satisfies the core requirements for sensor-based environmental observing
  systems. It facilitates the development of complex distributed streaming data
  applications and provides the foundation for reliable data acquisition and
  instrument management services. \cite{OSDT}
\end{description}


\subsubsection{Complexity}

The projects complexity is high, because of the following reasons:

\begin{itemize}
  \item two different technologies have to be integratged, it is not just one
  system to deal with.
  \item we have two different clients with different needs.
  \item at the beginning of the project we have no expertise is the existing
  systems.
  \item the used systems are research projects and still under
  development.
  \item the finished system will face high datatroughputs.
  \item our implementation will be difficult to test in the integtated system.
\end{itemize}

